Image forming apparatus

ABSTRACT

An image forming apparatus includes a photosensitive drum, a developing device, a toner container, a cleaner, a waste toner container, and a waste toner conveying pipe. The cleaner is configured to clean a peripheral surface of the photosensitive drum after a toner image has been transferred to the printing medium. The waste toner container is configured to accommodate therein waste toner removed from the peripheral surface of the photosensitive drum by the cleaner. The waste toner conveying pipe is configured to convey the waste toner from the cleaner to the waste toner container. The cleaner is located between the photosensitive drum and the fixing device in a vertical direction. The developing device is located below the photosensitive drum. The waste toner container is located below the cleaner. The toner container covers at least a part of an upper surface of the waste toner container.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application claiming priority benefitunder 35 U.S.C. 120 of pending U.S. patent application Ser. No.17/845,161 filed on Jun. 21, 2022, which claims priority to U.S. patentapplication Ser. No. 17/107,460 filed on Nov. 30, 2020 now U.S. Pat. No.11,409,223 issued on Aug. 9, 2022, which in turn claims priority to U.S.patent application Ser. No. 16/842,694 filed on Apr. 7, 2020 now U.S.Pat. No. 10,852,691 issued on Dec. 1, 2020, which in turn claimspriority to U.S. patent application Ser. No. 16/442,201 filed on Jun.14, 2019 now U.S. Pat. No. 10,691,059 issued on Jun. 23, 2020, which arebased upon and claim the benefit of priority under 35 U.S.C. 119 fromprior Japanese patent application No. 2018-116242, filed on Jun. 19,2018, the entire contents of all of which are incorporated herein byreference.

TECHNICAL FIELD

The present disclosure relates to an image forming apparatus.

BACKGROUND

In related art, an image forming apparatus includes a photosensitivedrum, a cleaner, a waste toner container, and a waste toner conveyingpipe. The cleaner is configured to remove waste toner from a peripheralsurface of the photosensitive drum after a toner image is transferred toa printing medium. In the waste toner container, waste toner removedfrom the peripheral surface of the photosensitive drum by the cleaner isaccommodated. The waste toner conveying pipe is configured to convey thewaste toner from the cleaner to the waste toner container.

In the image forming apparatus as disclosed in related art, the wastetoner conveying pipe is configured to convey the waste toner in asubstantially horizontal direction from the cleaner to the waste tonercontainer.

For this reason, the waste toner is likely to be accumulated in thevicinity of an inner surface of a lower side of the waste tonerconveying pipe. Also, when the accumulated waste toner is pushed andconsolidated between a screw and the inner surface of the waste tonerconveying pipe, the waste toner conveying pipe may be blocked.

SUMMARY

Aspect of non-limiting embodiments of the present disclosure provides animage forming apparatus including a cleaner located between aphotosensitive drum and a fixing device in a vertical direction andcapable of smoothly conveying waste toner from the cleaner to a wastetoner container.

Aspects of certain non-limiting embodiments of the present disclosureaddress the features discussed above and/or other features not describedabove. However, aspects of the non-limiting embodiments are not requiredto address the above features, and aspects of the non-limitingembodiments of the present disclosure may not address features describedabove.

An image forming apparatus configured to form an image on a printingmedium, the image forming apparatus including: a photosensitive drumrotatable relative to a rotary axis extending in an axial direction; anexposure device configured to expose the photosensitive drum to form alatent image on a peripheral surface of the photosensitive drum; adeveloping device including a developing roller configured to form atoner image by developing the latent image formed on the photosensitivedrum by toner; a toner container configured to accommodate therein tonerthat is to be supplied to the developing roller; a transfer rollerconfigured to transfer the toner image formed on the photosensitive drumto the printing medium; a fixing device configured to fix the tonerimage, which has been transferred to the printing medium, on theprinting medium, and being spaced upward from the photosensitive drum; acleaner configured to remove waste toner from a peripheral surface ofthe photosensitive drum after the toner image has been transferred tothe printing medium; a waste toner container configured to accommodatetherein the waste toner removed from the peripheral surface of thephotosensitive drum by the cleaner; and a waste toner conveying pipeconfigured to convey the waste toner from the cleaner to the waste tonercontainer, wherein the cleaner is located between the photosensitivedrum and the fixing device in a vertical direction, wherein thedeveloping device is located below the photosensitive drum, wherein thewaste toner container is located below the cleaner, and wherein thetoner container covers at least a part of an upper surface of the wastetoner container.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic configuration view of an image forming apparatusaccording to a first exemplary embodiment;

FIG. 2 depicts a state where a drawer shown in FIG. 1 is located at anouter position and a developing cartridge is demounted from the drawer;

FIG. 3 illustrates a scanning range of a laser scan unit shown in FIG. 1;

FIG. 4 is a plan view of the drawer shown in FIG. 1 ;

FIG. 5 is a sectional view taken along a line A-A of the drawer shown inFIG. 4 ;

FIG. 6 is a plan view of a drum cartridge shown in FIG. 1 ;

FIG. 7 is a sectional view taken along a line B-B of the drum cartridgeshown in FIG. 6 ;

FIG. 8 is a side view of the drum cartridge shown in FIG. 6 ;

FIG. 9 is a schematic configuration view of an image forming apparatusaccording to a second exemplary embodiment; and

FIG. 10 depicts a state where the drawer shown in FIG. 9 is located atan outer position.

DETAILED DESCRIPTION 1. Outline of Image Forming Apparatus of FirstExemplary Embodiment

Referring to FIGS. 1 to 3 , an outline of an image forming apparatus 1of a first exemplary embodiment is described.

As shown in FIG. 1 , the image forming apparatus 1 is configured to forman image on a printing medium P. The image forming apparatus 1 includesa main body housing 2, a feeder unit 3, a drawer 4, a drum cartridge 5,an exposure device 6, a developing cartridge 7, a transfer roller 8, anda fixing device 9.

1.1 Main Body Housing

The main body housing 2 is configured to accommodate therein the feederunit 3, the drawer 4, the drum cartridge 5, the exposure device 6, thedeveloping cartridge 7, the transfer roller 8, and the fixing device 9.The main body housing 2 has an opening 2A and a cover 2B.

The opening 2A is located at an opposite side to the transfer roller 8with respect to the drum cartridge 5 in a state where the drum cartridge5 is mounted to the main body housing 2.

The cover 2B is configured to be movable between an opening position(see FIG. 1 ) at which the opening 2A is opened and a closing position(see FIG. 2 ) at which the opening 2A is closed.

1.2 Feeder Unit

The feeder unit 3 is configured to feed the printing medium P to thephotosensitive drum 13. The printing medium P is a printing sheet, forexample. The photosensitive drum 13 will be described later. The feederunit 3 includes a cassette 10, a pickup roller 11, a feeder roller 12,and a conveying roller 17. The cassette 10 can accommodate therein theprinting medium P. The cassette 10 is mountable to the main body housing2. The cassette 10 is located below the drawer 4 located at an innerposition in a state where the cassette 2 is mounted to the main bodyhousing 2. The inner position at which the drawer 4 is located will bedescribed later. The pickup roller 11 is configured to pick up theprinting medium P in the cassette 10 and to convey the same toward thefeeder roller 12. The pickup roller 11 is located closer to the fixingdevice 9 than to the opening 2A in a horizontal direction in a statewhere the cover 2B is located at the closing position. The feeder roller12 is configured to convey the printing medium P from the pickup roller11 toward the conveying roller 17. The conveying roller 17 is configuredto convey the printing medium P from the feeder roller 12 toward thephotosensitive drum 13.

1.3 Drawer

As shown in FIGS. 1 and 2 , the drawer 4 is movable between an innerposition (see FIG. 1 ) and an outer position (see FIG. 2 ). When thedrawer 4 is located at the inner position, the drawer 4 is locatedinside the main body housing 2. When the drawer 4 is located at theouter position, the drawer 4 is located outside the main body housing 2.The drawer 4 is movable through the opening 2A between the innerposition and the outer position in the state where the cover 2B islocated at the opening position. The drawer 4 is configured to moveupward as the drawer 4 moves from the outer position toward the innerposition. In other words, the drawer 4 is configured to move downward asthe drawer 4 moves from the inner position toward the outer position.The drawer 4 is configured to support the drum cartridge 5 and thedeveloping cartridge 7. The drawer 4 is movable between the innerposition and the outer position while supporting the drum cartridge 5and the developing cartridge 7. The drawer 4 is configured to come intocontact with a part of the main body housing 2 and to be thus stopped atthe outer position.

Specifically, as shown in FIG. 2 , the main body housing 2 has a guidegroove 2C. The guide groove 2C extends in a moving direction of thedrawer 4. The guide groove 2C has a first end E1 and a second end E2 inthe moving direction of the drawer 4. The second end E2 is spaced fromthe first end E1 in the moving direction of the drawer 4. Also, thedrawer 4 has a projection 4A (see FIGS. 4 and 5 ). The projection 4A islocated on a side surface of the drawer 4 in an axial direction that isa direction in which a rotary axis A1 of the photosensitive drum 13extends. The projection 4A is fitted in the guide groove 2C. Thereby,the drawer 4 can move along the guide groove 2C. That is, the guidegroove 2C is configured to guide movement of the drawer 4. When thedrawer 4 is moved from the outer position toward the inner position, theprojection 4A is moved from the first end E1 toward the second end E2with being guided by the guide groove 2C. When the drawer 4 reaches theinner position, the projection 4A comes into contact with the second endE2 of the guide groove 2C, so that the drawer 4 is stopped at the innerposition. At this time, the photosensitive drum 13 comes into contactwith the transfer roller 8. Also, when the drawer 4 is moved from theinner position toward the outer position, the projection 4A comes intocontact with an inner surface of the first end E1 of the guide groove2C, i.e., a part of the main body housing 2 and is thus stopped at theouter position.

Also, the drawer 4 is supported by the cover 2B located at the openingposition in the state where it is located at the outer position. Thatis, in a state where the cover 2B is located at the opening position andthe drawer 4 is located at the outer position, the cover 2B supports thedrawer 4. Specifically, the cover 2B has a support part 2D. The supportpart 2D is in contact with a lower surface of the drawer 4 in the statewhere the cover 2B is located at the opening position and the drawer 4is located at the outer position. Thereby, the support part 2D supportsthe drawer 4 located at the outer position. Also, the support part 2Dhas a plurality of guide rollers 2E. The plurality of guide rollers 2Eis in contact with the lower surface of the drawer 4 in the state wherethe cover 2B is located at the opening position and the drawer 4 islocated at the outer position. Thereby, the drawer 4 can be smoothlymoved while being supported by the cover 2B.

Also, as shown in FIGS. 1 and 2 , the drawer 4 has a facing roller 18.In the state where the drawer 4 is located at the inner position, thefacing roller 18 is in contact with the conveying roller 17. In thestate where the facing roller 18 is in contact with the conveying roller17, the facing roller 18 can rotate as the conveying roller 17 rotates.Thereby, in the state where the drawer 4 is located at the innerposition, the facing roller 18 can convey the printing medium P from thefeeder roller 12 toward the photosensitive drum 13, together with theconveying roller 17. Also, when the drawer 4 is moved from the innerposition toward the outer position, the facing roller 18 separates fromthe conveying roller 17. Thereby, when the printing medium P is jammedbetween the conveying roller 17 and the facing roller 18, a user canremove the jammed printing medium P by locating the drawer 4 at theouter position to separate the facing roller 18 from the conveyingroller 17.

1.4 Drum Cartridge

As shown in FIG. 1 , the drum cartridge 5 is mountable to the drawer 4.The drum cartridge 5 includes the photosensitive drum 13 and a chargingroller 14. That is, the image forming apparatus 1 includes thephotosensitive drum 13.

The photosensitive drum 13 is configured to be rotatable about a rotaryaxis A1 extending in the axial direction. The axial direction intersectswith the moving direction of the drawer 4. Preferably, the axialdirection is perpendicular to the moving direction of the drawer 4. Thephotosensitive drum 13 extends in the axial direction and has acylindrical shape. Meanwhile, in the first exemplary embodiment, in thestate where the drum cartridge 5 and the developing cartridge 7 aremounted to the drawer 4 and the drawer 4 is located at the innerposition, the photosensitive drum 13 is located between the feederroller 12 and the fixing device 9 in a vertical direction.

The charging roller 14 is configured to charge a peripheral surface ofthe photosensitive drum 13. The charging roller 14 is in contact withthe peripheral surface of the photosensitive drum 13. In the meantime,the drum cartridge 5 may include a non-contact type charger such as ascorotron-type charger, instead of the charging roller 14.

1.5 Exposure Device

The exposure device 6 is configured to expose the photosensitive drum 13to form a latent image on a peripheral surface of the photosensitivedrum 13. Specifically, the exposure device 6 is configured to expose theperipheral surface of the photosensitive drum 13 charged by the chargingroller 14. Thereby, a latent image is formed on the peripheral surfaceof the photosensitive drum 13. The exposure device 6 is located abovethe drawer 4 located at the inner position. Specifically, the exposuredevice 6 is a laser scan unit configured to scan the peripheral surfaceof the photosensitive drum 13 with a laser light L. As shown in FIG. 3 ,the laser light L emitted from the exposure device 6 toward thephotosensitive drum 13 passes between a first drum side plate 31 and asecond drum side plate 32 of the drum cartridge 5 in the axial directionin the state where the drum cartridge 5 is mounted to the drawer 4 andthe drawer 4 is located at the inner position.

1.6 Developing Cartridge

As shown in FIG. 1 , the developing cartridge 7 is attachable to anddetachable from the drum cartridge 5. The developing cartridge 7includes a developing device 7A and a toner container 7B. That is, theimage forming apparatus 1 includes the developing device 7A and thetoner container 7B.

The developing device 7A includes a developing roller 16. That is, thedeveloping device 7A is a part of the developing cartridge 7 configuredto support the developing roller 16. The developing device 7A is locatedbelow the photosensitive drum 13 in the state where the drum cartridge 5and the developing cartridge 7 are mounted to the drawer 4.

The developing roller 16 is located below the photosensitive drum 13 inthe state where the drum cartridge 5 and the developing cartridge 7 aremounted to the drawer 4. The developing roller 16 is in contact with thephotosensitive drum 13 in the state where the drum cartridge 5 and thedeveloping cartridge 7 are mounted to the drawer 4. Thereby, thedeveloping roller 16 can supply toner in the developing cartridge 7 tothe photosensitive drum 13 in the state where the drum cartridge 5 andthe developing cartridge 7 are mounted to the drawer 4. The developingroller 16 is configured to supply the toner in the developing cartridge7 to the photosensitive drum 13, thereby developing a latent imageformed on the photosensitive drum 13 to form a toner image on theperipheral surface of the photosensitive drum 13. The developing roller16 is configured to be rotatable relative to a rotary axis A2. Therotary axis A2 of the developing roller 16 is parallel with the rotaryaxis A1 of the photosensitive drum 13. The developing roller 16 has ashaft 16A and a roller body 16B.

The shaft 16A extends in the axial direction along the rotary axis A2.The shaft 16A has a circular column shape. The shaft 16A penetrates theroller body 16B in the axial direction. The shaft 16A is made of metal.

The roller body 16B extends in the axial direction. The roller body 16Bhas a circular column shape. The roller body 16B is made of a conductiverubber.

The toner container 7B is configured to accommodate therein the tonerthat is to be supplied to the developing roller 16. That is, the tonercontainer 7B is a part of the developing cartridge 7 configured toaccommodate therein the toner. An internal space of the toner container7B communicates with an internal space of the developing device 7A.Thereby, the toner in the toner container 7B is supplied to thedeveloping roller 16 of the developing device 7A.

1.7 Transfer Roller

The transfer roller 8 is in contact with the photosensitive drum 13 inthe state where the drum cartridge 5 is mounted to the drawer 4 and thedrawer 4 is located at the inner position. The printing medium P fedfrom the cassette 10 passes between the transfer roller 8 and thephotosensitive drum 13. At this time, the transfer roller 8 isconfigured to transfer the toner image formed on the photosensitive drum13 to the printing medium P.

1.8 Fixing Device

The fixing device 9 is configured to heat and press the printing mediumP having the toner image transferred thereto, thereby fixing the tonerimage, which has been transferred to the printing medium P, on theprinting medium P. The fixing device 9 is located with being spacedupward from the photosensitive drum 13 in the state where the drumcartridge 5 is mounted to the drawer 4 and the drawer 4 is located atthe inner position. That is, the image forming apparatus 1 is equippedon a horizontal stand or the like so that the fixing device 9 is locatedabove the photosensitive drum 13.

2. Details of Drawer

Subsequently, details of the drawer 4 are described with reference toFIGS. 4 and 5 .

As shown in FIG. 4 , the drawer 4 includes a first drawer side plate 21,a second drawer side plate 22, and a bottom plate 23.

The first drawer side plate 21 is located at a first end of the drawer 4in the axial direction. The first drawer side plate 21 extends in themoving direction of the drawer 4. As shown in FIG. 5 , the first drawerside plate 21 has a first end E11 and a second end E12 in the movingdirection of the drawer 4. The second end E12 is spaced from the firstend E11 in the moving direction of the drawer 4. The second end E12 islocated downstream of the first end E11 in a direction in which thedrawer 4 moves from the inner position toward the outer position. Also,the first drawer side plate 21 has a guide 24, a through-hole 26, and anotch 27.

The guide 24 is located on an inner surface of the first drawer sideplate 21 in the axial direction. The guide 24 is concave in a directionof getting away from the second drawer side plate 22 in the axialdirection. The guide 24 is located between the first end E11 and thesecond end E12 in the moving direction of the drawer 4. The guide 24extends in a direction of intersecting with the moving direction of thedrawer 4. The guide 24 has a first end E21 and a second end E22. Thefirst end E21 is located closer to the first end E11 than the second endE22 in the moving direction of the drawer 4. The first end E21 isconnected to the notch 27. The second end E22 is located closer to thesecond end E12 than the first end E21 in the moving direction of thedrawer 4. The guide 24 is inclined downward from the second end E22toward the first end E21. In the state where the drawer 4 is located atthe outer position, the second end E22 (see FIG. 2 ) of the guide 24 isexposed to an outside from the opening 2A of the main body housing 2. Inthe state where the drawer 4 is located at the outer position, when thedrum cartridge 5 is being mounted to the drawer 4, the projection 5A(see FIG. 6 ) of the drum cartridge 5 is fitted in the guide 24.Thereby, in the state where the drawer 4 is located at the outerposition, when the drum cartridge 5 is being mounted to the drawer 4,the guide 24 guides the projection 5A of the drum cartridge 5.

The through-hole 26 is located below the guide 24 in the verticaldirection. The through-hole 26 has a circular shape. In the state wherethe developing cartridge 7 is attached to the drum cartridge 5 and thedrum cartridge 5 is mounted to the drawer 4, a developing coupling (notshown) of the developing cartridge 7 is exposed through the through-hole26. In the state where the developing cartridge 7 is attached to thedrum cartridge 5, the drum cartridge 5 is mounted to the drawer 4 andthe drawer 4 is located at the inner position, a first main bodycoupling (not shown) is coupled to the developing coupling. At thistime, the first main body coupling is inserted in the through-hole 26.

The notch 27 is connected to the first end E21 of the guide 24. Thenotch 27 has a semicircular shape. In the state where the drum cartridge5 is mounted to the drawer 4, the projection 5A of the drum cartridge 5is fitted in the notch 27 and a drum coupling 100 (see FIG. 6 ) isexposed through the notch 27. In the state where the drum cartridge 5 ismounted to the drawer 4 and the drawer 4 is located at the innerposition, a second main body coupling (not shown) is coupled to the drumcoupling 100. At this time, the second main body coupling is inserted inthe notch 27.

As shown in FIG. 4 , the second drawer side plate 22 is located at asecond end of the drawer 4 in the axial direction. The second drawerside plate 22 is spaced from the first drawer side plate 21 in the axialdirection. The second drawer side plate 22 has the same shape as thefirst drawer side plate 21, except that it is not formed with thethrough-hole 26.

The bottom plate 23 is located between the first drawer side plate 21and the second drawer side plate 22 in the axial direction. The bottomplate 23 extends in the axial direction. A first end of the bottom plate23 in the axial direction is connected to the first drawer side plate21. A second end of the bottom plate 23 in the axial direction isconnected to the second drawer side plate 22. The bottom plate 23 has anopening 23A.

The opening 23A extends in the axial direction. In the state where thedrawer 4 is located at the inner position and the cover 2B is located atthe closing position, two pressing members 110A, 110B provided in themain body housing 2 are located in the opening 23A.

In the meantime, as shown in FIGS. 1 and 2 , the pressing member 110A ismovable through the opening 23A between a pressing position (see FIG. 1) and a press-releasing position (see FIG. 2 ).

The pressing member 110A is connected to the cover 2B via a bar 111 anda tension spring 112. The pressing member 110A is configured to movefrom the press-releasing position to the pressing position, inconjunction with movement of the cover 2B from the opening position tothe closing position. As shown in FIG. 1 , in a state where thedeveloping cartridge 7 is attached to the drum cartridge 5, the drumcartridge 5 is mounted to the drawer 4, the drawer 4 is located at theinner position, and the cover 2B is located at the closing position, thepressing member 110A is located at the pressing position. Then, thepressing member 110A presses the developing device 7A of the developingcartridge 7 toward the photosensitive drum 13. Thereby, the developingroller 16 is pressed to the photosensitive drum 13.

Also, the pressing member 110A is configured to move from the pressingposition to the press-releasing position, in conjunction with movementof the cover 2B from the closing position to the opening position. Asshown in FIG. 2 , in the state where the cover 2B is located at theopening position, the pressing member 110A is located at thepress-releasing position. Then, the pressed state of the developingdevice 7A by the pressing member 110A is released.

3. Details of Drum Cartridge

Subsequently, details of the drum cartridge 5 are described withreference to FIGS. 6 to 8 .

As shown in FIG. 6 , the drum cartridge 5 includes a first drum sideplate 31, a second drum side plate 32, a cleaner 33, a waste tonercontainer 34, and a waste toner conveying pipe 35, in addition to thephotosensitive drum 13 and the charging roller 14. That is, the imageforming apparatus 1 includes the cleaner 33, the waste toner container34, and the waste toner conveying pipe 35.

3.1 First Drum Side Plate and Second Drum Side Plate

The first drum side plate 31 is located at a first end of the drumcartridge 5 in the axial direction. The first drum side plate 31 extendsin a direction of intersecting with the axial direction. Preferably, thefirst drum side plate 31 extends in a direction perpendicular to theaxial direction. The first drum side plate 31 has a projection 5A, aguide 36, and a through-hole 37 (see FIG. 7 ).

The projection 5A is located on an outer surface of the first drum sideplate 31 in the axial direction. In other words, the projection 5A islocated at an opposite side to the second drum side plate 32 withrespect to the first drum side plate 31 in the axial direction. Theprojection 5A extends in the axial direction. The projection 5A has acylindrical shape. The projection 5A is configured to cover a peripheralsurface of the drum coupling 100. That is, the guide 24 guides the drumcoupling 100 to the notch 27 when the drum cartridge 5 is being mountedto the drawer 4 in the state where the drawer 4 is located at the outerposition. The drum coupling 100 is mounted to the first end of thephotosensitive drum 13 in the axial direction and can be thus rotatedtogether with the photosensitive drum 13. In the state where the drumcartridge 5 is mounted to the drawer 4 and the drawer 4 is located atthe inner position, the drum coupling 100 is fed with power from theimage forming apparatus 1.

As shown in FIG. 7 , the guide 36 is located below the rotary axis A1 ofthe photosensitive drum 13 in the state where the drum cartridge 5 ismounted to the drawer 4. The shaft 16A (see FIG. 1 ) of the developingroller 16 is fitted in the guide 36 when the developing cartridge 7 isbeing attached to the drum cartridge 5. Thereby, the guide 36 guides theshaft 16A of the developing roller 16 when the developing cartridge 7 isbeing attached to the drum cartridge 5. The guide 36 has a first part36A and a second part 36B.

The first part 36A extends in a direction of intersecting with themoving direction of the drawer 4 in the state where the drum cartridge 5is mounted to the drawer 4. The first part 36A extends in a direction inwhich the first part 36A faces downward as it comes close to thephotosensitive drum 13.

The second part 36B is located between the first part 36A and thephotosensitive drum 13. The second part 36B extends in a direction ofintersecting with the direction in which the first part 36A extends.Specifically, the second part 36B extends in a direction of connectingthe rotary axis A1 of the photosensitive drum 13 and the rotary axis A2(see FIG. 1 ) of the developing roller 16 in the state where thedeveloping cartridge 7 is attached to the drum cartridge 5 and the drumcartridge 5 is mounted to the drawer 4. The second part 36B is connectedto the first part 36A.

The through-hole 37 is formed at an intermediate position of the guide36. The through-hole 37 has a circular shape. In the state where thedeveloping cartridge 7 is attached to the drum cartridge 5, thethrough-hole 37 is aligned in a line with the through-hole 26 (see FIG.5 ) of the drawer 4 in the axial direction. Thereby, in the state wherethe developing cartridge 7 is attached to the drum cartridge 5 and thedrum cartridge 5 is mounted to the drawer 4, the first main bodycoupling is coupled to the developing coupling via the through-hole 26and the through-hole 37.

As shown in FIG. 6 , the second drum side plate 32 is located at asecond end of the drum cartridge 5 in the axial direction. The seconddrum side plate 32 is spaced from the first drum side plate 31 in theaxial direction. The second drum side plate 32 has a projection 5B. Inthe meantime, the second drum side plate 32 has the same shape as thefirst drum side plate 31, except that it is not formed with thethrough-hole 37 and has the projection 5B.

The projection 5B is located on an outer surface of the second drum sideplate 32 in the axial direction. In other words, the projection 5B islocated at an opposite side to the first drum side plate 31 with respectto the second drum side plate 32 in the axial direction. The projection5B extends in the axial direction. The projection 5B has a circularcolumn shape. The projection 5B is fitted in the guide 24 (see FIG. 4 )of the second drawer side plate 22 and is guided to the notch 27 by theguide 24 when the drum cartridge 5 is being mounted to the drawer 4.Thereby, the guide 24 of the second drawer side plate 22 guides theprojection 5B of the drum cartridge 5 when the drum cartridge 5 is beingmounted to the drawer 4 in the state where the drawer 4 is located atthe outer position.

3.2 Cleaner

As shown in FIG. 7 , the cleaner 33 is located around the photosensitivedrum 13. The cleaner 33 is located between the photosensitive drum 13and the fixing device 9 (see FIG. 1 ) in the vertical direction in thestate where the drum cartridge 5 is mounted to the drawer 4 and thedrawer 4 is located at the inner position. The cleaner 33 is configuredto remove waste toner from the peripheral surface of the photosensitivedrum 13 after the toner image is transferred to the printing medium P.Specifically, the cleaner 33 includes a cleaner frame 33A, a cleaningblade 33B, and a screw 33C.

As shown in FIG. 6 , the cleaner frame 33A is located between the firstdrum side plate 31 and the second drum side plate 32 in the axialdirection. The cleaner frame 33A extends in the axial direction. A firstend of the cleaner frame 33A in the axial direction is connected to thefirst drum side plate 31. A second end of the cleaner frame 33A in theaxial direction is connected to the second drum side plate 32. As shownin FIG. 7 , the cleaner frame 33A has an opening 33D. The opening 33Dfaces the peripheral surface of the photosensitive drum 13. The opening33D communicates with an internal space of the cleaner frame 33A. Theopening 33D extends in the axial direction.

The cleaning blade 33B is attached to the cleaner frame 33A. An endportion of the cleaning blade 33B is located in the opening 33D. The endportion of the cleaning blade 33B is in contact with the peripheralsurface of the photosensitive drum 13. Thereby, when the photosensitivedrum 13 is rotated, the waste toner remaining on the peripheral surfaceof the photosensitive drum 13 is scraped by the cleaning blade 33B andis then accommodated in the internal space of the cleaner frame 33Athrough the opening 33D. Thereby, the cleaner 33 removes the waste tonerfrom the peripheral surface of the photosensitive drum 13.

The screw 33C is located in the cleaner frame 33A. The screw 33C extendsin the axial direction. Thereby, the screw 33C is configured to conveythe waste toner accommodated in the cleaner frame 33A in the axialdirection.

3.3 Waste Toner Container

As shown in FIG. 7 , the waste toner container 34 is spaced from thecleaner 33. Specifically, the waste toner container 34 is spaced fromthe cleaner 33 in the moving direction of the drawer 4 in the statewhere the drum cartridge 5 is mounted to the drawer 4. The waste tonercontainer 34 is located below the cleaner 33 in the state where the drumcartridge 5 is mounted to the drawer 4. The waste toner container 34 isconfigured to accommodate therein the waste toner removed from theperipheral surface of the photosensitive drum 13 by the cleaner 33.Specifically, the waste toner removed from the peripheral surface of thephotosensitive drum 13 by the cleaner 33 is conveyed from the cleaner 33to the waste toner container 34 by the waste toner conveying pipe 35(see FIG. 8 ). The waste toner container 34 is configured to accommodatetherein the waste toner conveyed by the waste toner conveying pipe 35.The waste toner container 34 extends in the axial direction and has abox shape. An upper surface S1 of the waste toner container 34 extendsin the same direction as the first part 36A of the guide 36. The uppersurface S1 of the waste toner container 34 extends in a direction inwhich the upper surface S1 faces downward as it comes close to thephotosensitive drum 13. As shown in FIG. 1 , the upper surface S1 of thewaste toner container 34 is in contact with a lower surface S2 of thetoner container 7B of the developing cartridge 7 in the state where thedeveloping cartridge 7 is attached to the drum cartridge 5. That is, thetoner container 7B is configured to cover at least a part of the uppersurface of the waste toner container 34 in the state where thedeveloping cartridge 7 is attached to the drum cartridge 5.

3.4 Waste Toner Conveying Pipe

As shown in FIG. 6 , the waste toner conveying pipe 35 is configured toconnect the cleaner 33 and the waste toner container 34. The waste tonerconveying pipe 35 is configured to convey the waste toner from thecleaner 33 to the waste toner container 34. Specifically, a screw 35Afor conveying the waste toner is located in the waste toner conveyingpipe 35. The screw 35A is a shaftless screw. The waste toner conveyingpipe 35 is configured to pass an outer side of the second drum sideplate 32 in the axial direction. In other words, the waste tonerconveying pipe 35 is configured to pass an opposite side to the firstdrum side plate 31 with respect to the second drum side plate 32 in theaxial direction. Also, the waste toner conveying pipe 35 is configuredto pass an outer side of a scanning range (see FIG. 3 ) of the laserlight L from the exposure device 6 in the axial direction. As shown inFIG. 8 , in the state where the drum cartridge 5 is mounted to thedrawer 4, the waste toner conveying pipe 35 extends downward as thewaste toner conveying pipe 35 faces from the cleaner 33 (see FIG. 7 )toward the waste toner container 34, as seen from the axial direction.Thereby, it is possible to convey the waste toner from the cleaner 33toward the waste toner container 34 by using the gravity. For thisreason, it is possible to smoothly convey the waste toner from thecleaner 33 toward the waste toner container 34. As shown in FIG. 1 , inthe state where the developing cartridge 7 is attached to the drumcartridge 5, the waste toner conveying pipe 35 intersects with the tonercontainer 7B, as seen from the axial direction.

4. Mounting of Drum Cartridge and Developing Cartridge to Drawer

Subsequently, mounting of the drum cartridge 5 and the developingcartridge 7 to the drawer 4 is described.

When the drum cartridge 5 is being mounted to the drawer 4, theprojection 5A (see FIG. 6 ) is fitted in the guide 24 (see FIG. 4 ) ofthe first drawer side plate 21 and the projection 5B (see FIG. 6 ) isfitted in the guide 24 (see FIG. 4 ) of the second drawer side plate 22in the state where the drawer 4 is located at the outer position, sothat the drum cartridge 5 is guided from the outside of the main bodyhousing 2 toward the inside of the main body housing 2.

Then, when the projection 5A is fitted in the notch 27 of the firstdrawer side plate 21 and the projection 5B is fitted in the notch 27 ofthe second drawer side plate 22, the mounting of the drum cartridge 5 tothe drawer 4 is completed, as shown in FIG. 2 .

In the state where the drum cartridge 5 is mounted to the drawer 4, atleast a part of the drum cartridge 5 is located in the main body housing2. Specifically, in the state where the drum cartridge 5 is mounted tothe drawer 4 and the drawer 4 is located at the outer position, thephotosensitive drum 13 and the second part 36B of the guide 36 arelocated in the main body housing 2. On the other hand, in the statewhere the drum cartridge 5 is mounted to the drawer 4 and the drawer 4is located at the outer position, the first part 36A of the guide 36 ofthe drum cartridge 5 is located outside the main body housing 2.

Then, in the state where the cover 2B is located at the opening positionand the drawer 4 is located at the outer position, the developingcartridge 7 is attachable to and detachable from the drum cartridge 5with the drum cartridge 5 being mounted to the drawer 4. When thedeveloping cartridge 7 is being attached to the drum cartridge 5, theshaft 16A of the developing roller 16 is guided by the guide 36 of thedrum cartridge 5 in the state where the drum cartridge 5 is mounted tothe drawer 4 and the drawer 4 is located at the outer position. Also, atthis time, the upper surface S1 of the waste toner container 34 comesinto contact with the lower surface S2 of the developing cartridge 7, sothat the waste toner container 34 guides the developing cartridge 7.Then, as shown in FIG. 1 , when the shaft 16A of the developing roller16 is fitted in the second part 36B of the guide 36 and the developingroller 16 comes into contact with the photosensitive drum 13, theattaching of the developing cartridge 7 to the drum cartridge 5 iscompleted.

5. Operational Effects

As shown in FIG. 1 , according to the image forming apparatus 1, thewaste toner conveying pipe 35 conveys the waste toner from the cleaner33, which is located between the photosensitive drum 13 and the fixingdevice 9 in the vertical direction, to the waste toner container 34located below the cleaner 33.

Thereby, it is possible to convey the waste toner, which has beenremoved from the peripheral surface of the photosensitive drum 13 by thecleaner 33, from the cleaner 33 to the waste toner container 34 by usingthe gravity.

As a result, it is possible to smoothly convey the waste toner from thecleaner 33 to the waste toner container 34.

Also, as shown in FIG. 2 , according to the image forming apparatus 1,the cover 2B supports the drawer 4 in the state where the cover 2B islocated at the opening position and the drawer 4 is located at the outerposition.

Thereby, it is possible to stably support the drawer 4 at the outerposition and to smoothly replace the drum cartridge 5 and the developingcartridge 7.

Also, as shown in FIG. 2 , according to the image forming apparatus 1,the developing cartridge 7 is attachable to and detachable from the drumcartridge 5 with the drum cartridge 5 being mounted to the drawer 4 inthe state where the cover 2B is located at the opening position and thedrawer 4 is located at the outer position.

Thereby, it is possible to replace only the developing cartridge 7without demounting the drum cartridge 5 from the drawer 4.

For this reason, it is possible to simply replace the developingcartridge 7. At this time, since the toner container 7B of thedeveloping cartridge 7 is located above the waste toner container 34,the waste toner container 34 does not interfere the operations ofattaching and detaching the developing cartridge 7.

Also, as shown in FIG. 2 , according to the image forming apparatus 1,when the developing cartridge 7 is being attached to the drum cartridge5, the upper surface S1 of the waste toner container 34 may come intocontact with the lower surface S2 of the toner container 7B of thedeveloping cartridge 7, so that the waste toner container 34 guides thedeveloping cartridge 7.

Thereby, while supporting the developing cartridge 7 with the uppersurface S1 of the waste toner container 34, it is possible to attach thedeveloping cartridge 7 to the drum cartridge 5.

For this reason, it is possible to smoothly replace the developingcartridge 7. In particular, even when the developing cartridge 7 islarge and heavy, it is possible to smoothly replace the developingcartridge 7.

6. Second Exemplary Embodiment

Subsequently, a second exemplary embodiment is described with referenceto FIGS. 9 and 10 . In the second exemplary embodiment, the same membersas the first exemplary embodiment are denoted with the same referencenumerals, and the descriptions thereof are omitted.

6.1 Sheet Feeding Tray

As shown in FIG. 9 , the image forming apparatus 1 of the secondexemplary embodiment has a second opening 200, and includes a sheetfeeding tray 201, a second pickup roller 202, and a second feeder roller203.

The second opening 200 is provided to the cover 2B.

The sheet feeding tray 201 is a so-called multi manual sheet feedingtray. The user can put a plurality of printing media P2 on the sheetfeeding tray 201 through the second opening 200. The printing medium P2is usually a printing medium different from the printing medium P (seeFIG. 1 ). For example, when the printing medium P is an A4-sizedprinting sheet, the printing medium P2 is a postcard and the like. Theplurality of printing media P2 put on the sheet feeding tray 201 isintroduced one by one into the main body housing 2 through the secondopening 200 by the second pickup roller 202. In the meantime, the sheetfeeding tray 201 has a first part 201A and a second part 201B.

The first part 201A is mounted to an outer surface of the cover 2B. Thefirst part 201A is configured to be movable relative to the cover 2Bbetween a first position shown with the solid line in FIG. 9 and asecond position shown with the virtual line in FIG. 9 , in the statewhere the cover 2B is located at the closing position. The sheet feedingtray 201 is configured to be pivotable relative to a shaft A11 betweenthe first position and the second position. When the cover 2B is locatedat the closing position and the first part 201A is located at the firstposition, the first part 201A is located at an opposite side to thesecond part 201B with respect to the second opening 200 of the cover 2B.When the cover 2B is located at the closing position and the first part201A is located at the first position, the first part 201A extends insubstantially the horizontal direction. Also, when the cover 2B islocated at the closing position and the first part 201A is located atthe second position, the first part 201A extends in the verticaldirection along the outer surface of the cover 2B.

The second part 201B is located in the main body housing 2.Specifically, the second part 201B is located between the drawer 4 andthe cassette 10 in the vertical direction in the state where the drawer4 is located at the inner position. The second part 201B is locatedbetween the second pickup roller 202 and the first part 201A in thehorizontal direction in the state where the cover 2B is located at theclosing position and the first part 201A is located at the firstposition. The second part 201B extends in substantially the horizontaldirection. The second part 201B is connected to the first part 201A inthe state where the cover 2B is located at the closing position. In themeantime, the connection between the first part 201A and the second part201B is released in the state where the cover 2B is located at theopening position.

The second pickup roller 202 is configured to convey the printing mediumP put on the sheet feeding tray 201 toward the second feeder roller 203.The second pickup roller 202 is located closer to the fixing device 9than to the opening 2A in the horizontal direction in the state wherethe cover 2B is located at the closing position. Thereby, it is possibleto make the main body housing 2 thin at a side at which the cover 2B isprovided. The second pickup roller 202 is located between the drawer 4and the cassette 10 in the vertical direction in the state where thedrawer 4 is located at the inner position.

The second feeder roller 203 is configured to convey the printing mediumP from the second pickup roller 202 toward the conveying roller 17. Thesecond feeder roller 203 is located at an opposite side to the secondopening 200 with respect to the second pickup roller 202, in the statewhere the cover 2B is located at the closing position. The second feederroller 203 is located between the drawer 4 and the cassette 10 in thevertical direction in the state where the drawer 4 is located at theinner position.

6.2 Transfer Roller

In the image forming apparatus 1 of the second exemplary embodiment, thetransfer roller 8 is provided to the drum cartridge 5. Thereby, in astate where the drum cartridge 5 is demounted from the image formingapparatus 1, it is possible to cover and protect the photosensitive drum13 with the transfer roller 8.

6.3 Operational Effects of Second Exemplary Embodiment

Also in the second exemplary embodiment, it is possible to accomplishthe same operational effects as the first exemplary embodiment.

The foregoing description of the exemplary embodiments of the presentinvention has been provided for the purposes of illustration anddescription. It is not intended to be exhaustive or to limit theinvention to the precise forms disclosed. Obviously, many modificationsand variations will be apparent to practitioners skilled in the art. Theembodiments were chosen and described in order to best explain theprinciples of the invention and its practical applications, therebyenabling others skilled in the art to understand the invention forvarious embodiments and with the various modifications as are suited tothe particular use contemplated. It is intended that the scope of theinvention be defined by the following claims and their equivalents.

What is claimed is:
 1. An image forming apparatus configured to form animage on a printing medium, the image forming apparatus comprising: aphotosensitive drum rotatable relative to a rotary axis extending in anaxial direction; an exposure device configured to expose thephotosensitive drum to laser light beam to form a latent image on aperipheral surface of the photosensitive drum; a developing deviceincluding a developing roller configured to form a toner image bydeveloping the latent image formed on the photosensitive drum by toner;a toner container configured to accommodate therein toner that is to besupplied to the developing roller; a cleaner configured to remove wastetoner from a peripheral surface of the photosensitive drum after thetoner image has been transferred to the printing medium; a waste tonercontainer configured to accommodate therein the waste toner removed fromthe peripheral surface of the photosensitive drum by the cleaner; and awaste toner conveying pipe configured to convey the waste toner from thecleaner to the waste toner container, the waste toner conveying pipeincluding a conveying member, wherein the waste toner conveying pipe islocated outside an exposure range of the laser light beam when viewedfrom a vertical direction, and intersects the laser light beam whenviewed from the axial direction.
 2. The image forming apparatusaccording to claim 1, further comprising: wherein a first side plate anda second side plate configured to support both ends of thephotosensitive drum in the axial direction, and wherein a part of thewaste toner conveying pipe is located at an opposite side to the firstside plate with respect to the photosensitive drum.
 3. The image formingapparatus according to claim 2, wherein the exposure device isconfigured to expose the photosensitive drum to laser light beam betweenthe first side plate and the second side plate.
 4. The image formingapparatus according to claim 2, wherein the waste toner conveying pipeis connected to the waste toner container at the opposite side to thefirst side plate with respect to the photosensitive drum.
 5. The imageforming apparatus according to claim 2, wherein the toner container islocated between the first side plate and the second side plate whenviewed from the vertical direction, and wherein the waste tonerconveying pipe intersects the toner container when viewed from the axialdirection.
 6. The image forming apparatus according to claim 5, whereinthe toner container configured to attach to and detach from the firstside plate and the second side plate, and wherein the first side plateand the second side plate each has an attaching and detaching guide. 7.The image forming apparatus according to claim 6, wherein the wastetoner conveying pipe is located farther from the toner container thanthe attaching and detaching guide in the axial direction.
 8. The imageforming apparatus according to claim 6, wherein the attaching anddetaching guide is configured to guide a developing cartridge includingthe developing device and the toner container.
 9. The image formingapparatus according to claim 4, wherein the waste toner container has arear end, and wherein the waste toner conveying pipe is connected to therear end of the waste toner container.